can't get engine height correct

columbiachop · 03 June 2006, 05:45

ok, i think my head is going to pop off.

i ended up with a XL shaft (25") 40hp evinrude motor for my Commando C5 sib instead of the recommended long shaft. i really want to make it work so i spent $200 on a transom riser.

now water still splashes in over the transom when on plane. i tried mounting in every hole but still splashes in. so frusterating. have i made a huge mistake by trying to make an XL work on a transom made for a long shaft?

i have the cavitation plate two inches above the keel at the momment, but tried it an inch lower too with no luck.

any ideas would be great.

kitten · 03 June 2006, 06:11

You could try moving the sender, And/or find some way of making the bottem of the transom sharper to allow the water to break cleaner from the hull.

columbiachop · 03 June 2006, 06:25

the previous owner had those dole-fins things that bolt onto the cavitation plate. i wonder if this was how he fixed it? this is a different motor but i still have them.

tue · 03 June 2006, 08:32

doel fins won't solve the problem (they'll probably create more, do a search for doel fins on here!). The spray is coming from in front of the engine, so as Kitten said move the sender to one side.

jwalker · 03 June 2006, 09:50

Lower the engine a fair distance. The hull of your C5 when underway will have a big hook in it because it is made from flexible fabric and unsupported except at the keel and transom. The water leaves the transom at a downward angle. I mounted my motor with the anti-ventilation plate 25mm below the transom on my C5. Sibs do tend to be a bit splashy at the stern because the transom corner is not too sharp. Also, the water flow of the hull is a bit disorganised.

columbiachop · 03 June 2006, 14:53

ok, i'm on it. i'll move the transducer over and drop the engine slightly.

thanks a bunch guys.

andy

jyasaki · 20 June 2006, 19:49

FWIW, I saw a guy with a large SIB (Bombard 18'er?) who had the same problem. He rigged a large sheet of nylon stretched between the tubes at the back to knock the spray down (with a cut-out for the motor.)

Some boats just kick up more than others, I think.

jky